Corrugated boxes are typically produced in large machines which have several sections, each of which performs one or more steps in the mass production of the boxes. These sections often include an inking section, a gluing section, a folding section, a delivery section and a stacking section.
In operation, corrugated board is sent into the inking section of the corrugated box machine. Here the board is cut, printed and scored for folding. From the inking section the board travels into the gluing section where a bead of glue is applied along one edge of the board. The board then travels into the folding section where long rotating belts convey the board and cause the outer edges of the board to be folded inwardly along the score lines. As the edges fold over, the glued edge is folded onto the unglued edge to form a seal. Once the board is glued, folded and sealed, it then passes into the delivery section which facilitates the transfer of the finished corrugated box from the folding section into the stacking section where the boxes are readied for shipment.
Many corrugated box machines utilize what is termed an "upstacking" unit in the stacking section of the machine. As the name implies, an upstacking unit stacks boxes from the bottom up with each new box being fed into the bottom of the stack. Due to the nature of the prior art equipment, it is not uncommon for the newly formed boxes to become bent and jammed as they are transferred from the folding section into the stacking section via the delivery apparatus. It is therefore an object of the present invention to provide a corrugated box machine with a delivery apparatus which will facilitate the transfer of boxes from the folding to the stacking section and reduce the tendency of the boxes to jam during this procedure.
The corrugated board is conveyed through the machine by drive belts which grip the sides of the board. One set of belts is used to convey the board through the inking, gluing, folding and delivery sections of the machine while a separate set of belts are used in the stacking section. Because the stacking section stacks the boxes from the bottom up, a pair of spiral lifting gears are disposed between the delivery and stacking section belts to lift the box stack and allow the exiting boxes to be fed into the bottom of the stack.
The rotation of the spiral lifting gears is timed with the rotation of the belts. Consequently, when the belts stretch, the timing goes off and there is an increased risk of the boxes jamming as they enter the spiral lifting gears. In addition, not all thickness of boxes can be run using the same spiral lifting gear. As a result, it is sometimes necessary to stop the machine and change the spiral lifting gears to accomodate a production run of boxes of a different thickness. It is therefore an object of the present invention to provide a simplified and improved mechanism for conveying boxes into the stacking section of a corrugated box machine which does not require the use of spiral lifting gears.
After the newly formed boxes have gone into the spiral lifting gears, the leading edges of the boxes abut a vertical stop plate which serves to align the boxes prior to their being removed from the stack in predetermined lots. Newly formed corrugated boxes will often have box chips partially attached to them as a result of the cutting process. As the boxes move toward the stop plate, the box chips will oftentimes break away from the boxes and cause one of several problems relative to the stop plate. One problem is that the chips get caught in the holes in the stop plate where the belts pass through the plate. If this happens, the belts jam thus necessitating the stopping of the machine so that the box chips can be manually cleared from the stop plate. Another problem involves the chips exerting undue pressure on the belts which causes friction and premature wearing and replacement of the belts. This extra friction can also cause the lacings on the belts to wear through and the belts to separate. Finally, if the box chips get caught between the box and the stop plate, they can prevent the boxes from abutting the stop plate which in turn can cause jamming of the boxes in the spiral lifting gears. It is therefore another object of the present invention to provide a stop plate and belt assembly for the stacking section of a corrugated box machine which reduces the tendency of jamming due to box chip build-up.
The prior art stop plate used to align the leading edges of the boxes also has a vertical front surface with a driven knurled wheel positioned midway up the vertical front surface. The purpose of the knurled wheel is to help move the boxes up the plate. However, the knurled wheel also grinds material off the leading edges of the boxes which eventually clogs the wheels and they then become inoperable. It is therefore an object of the present invention to provide a simplified stop plate which will reduce the binding and clogging problems as the boxes move up the stop plate.
Other objects and advantages of the present invention will become apparent as the invention is described hereinafter in detail and with reference to the accompanied drawings.